Various types of coordinated controls have been proposed and used for controlling construction equipment such as backhoes (see Canadian Patent No. 1,060,562 issued Aug. 14, 1979 to Parquet et al) or for controlling the orientation of a hydraulic boom, for example, for positioning a rock drill for drilling (Canadian Patent No. 1,203,309 issued Apr. 15, 1986 to Saulters et al).
In the Parquet Canadian patent 1,060,562, there is described a system for automatically setting the position of an implement with respect to the frame by a combination of position sensors and activators.
Canadian Patent No. 1,203,309 to Saulters et al provides a system for maintaining the free end of an arm carrying a drill at a constant orientation when transferring the drill from one position to another, i.e. from one bore hole to another while maintaining the same angle to the horizontal. In the Saulters et al patent, the concept is to select a second position and then move the boom to the second position while maintaining the proper orientation.
Other devices of maintaining orientation of equipment are known, for example, in farm machinery devices are available for maintaining the orientation and space relationship of a mower and pick up system on a combine as shown for example in U.S. Pat. No. 4,518,044 issued May 21, 1985 to Wiegardt.
It is also well known to program equipment such as a robot to perform the same task repetitively by programming coordinates and having the articulated arms of the robot move between the designated points defined by such coordinates or to move on a designated trajectory between points.
Other control techniques have been applied to construction equipment see for example U.S. Pat. Nos. 3,339,763 and 3,414,146 which disclose hydraulic circuits that will function to automatically perform elected operations of a backhoe or U.S. Pat. No. 3,698,580 to Carlson which utilizes electric rather than hydraulic control to obtain similar operations.